Microstructure and Electric Properties of Bi2O3-Doped (K0.5Na0.5)NbO3 Lead-Free Ceramics

In this paper, Bi2O3-doped (K0.5Na0.5)NbO3(x = 0.1, 0.2, 0.3, 0.4) lead-free ceramics are prepared by a conventional solid-state reaction and analyzed by studying the structure, ferroelectric, and piezoelectric properties. It is found that the doping of Bi2O3increases the proportion of the trigonal phase in KNN ceramics, thus enabling the construction of KNN ceramics with an orthogonal–trigonal phase boundary at room temperature. At the same time, doping with Bi2O3can reduce the grain size and improve grain size uniformity of the ceramics. The KNN-0.1%Bi2O3ceramic has the best piezoelectric properties in all composition; the results are as follows:d33= 121pC/N,kp= 0.474,kt= 0.306.Keywords:KNN lead-free ceramics;Bi2O3doping;grain effects;piezoelectric property